Re: [PATCH v2 05/12] software_node: unregister software_nodes in reverse order

[Sakari Ailus]

Hi Daniel,

On Thu, Dec 17, 2020 at 11:43:30PM +0000, Daniel Scally wrote:
> To maintain consistency with software_node_unregister_nodes(), reverse
> the order in which the software_node_unregister_node_group() function
> unregisters nodes.
> 
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> Suggested-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Signed-off-by: Daniel Scally <djrscally@xxxxxxxxx>
> ---
> Changes in v2:
> 
> 	- Initialised i properly
> 
>  drivers/base/swnode.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c
> index cfd1faea48a7..2b90d380039b 100644
> --- a/drivers/base/swnode.c
> +++ b/drivers/base/swnode.c
> @@ -778,16 +778,22 @@ EXPORT_SYMBOL_GPL(software_node_register_node_group);
>   * software_node_unregister_node_group - Unregister a group of software nodes
>   * @node_group: NULL terminated array of software node pointers to be unregistered
>   *
> - * Unregister multiple software nodes at once.
> + * Unregister multiple software nodes at once. The array will be unwound in
> + * reverse order (I.E. last entry first) and thus if any member of the array
> + * has its .parent member set then they should appear later in the array such
> + * that they are unregistered first.
>   */
>  void software_node_unregister_node_group(const struct software_node **node_group)
>  {
> -	unsigned int i;
> +	unsigned int i = 0;
>  
>  	if (!node_group)
>  		return;
>  
> -	for (i = 0; node_group[i]; i++)
> +	while (node_group[i]->name)

Why is this change made? node_group is a NULL-terminated array, and the
above accesses the name pointer on each entry before checking the entry is
non-NULL. Or do I miss something here?

> +		i++;
> +
> +	while (i--)
>  		software_node_unregister(node_group[i]);
>  }
>  EXPORT_SYMBOL_GPL(software_node_unregister_node_group);

-- 
Regards,

Sakari Ailus